Electric lamps



Feb. 1, 1966 F. A. CAINE 3,233,095

ELECTRIC LAMPS Filed Aug. 12. 1963 United States Patert O 3,233,095ELECTRIC LAlVlPS Frank Alexander Caine, Coventry, England, assignor toHumber Limited, Coventry, England, a British company Filed Aug. 12,1963, Ser. No. 301,550 Claims priority, application Great Britain, Aug.15, 1962, 31,359/62 4 Claims. (CI. %RO-46.03)

The invention relates to electric lamps of the kind having a lamp bulbheld in housing having an aperture covered by a transparent ortranslucent member. Such lamps are used, for example, as indicator lampson motor vehicles to give a visual indication of the functioning ofvarious devices such as headlamps, direction indicators, and overdrive,although the invention is not restricted in its application to suchindicator lamps. When lamps of this kind are required to be used both indaylight and at night it is sometimes found that a lamp brilliance, asseen through the transparent or translucent member, which is suitablefor use in daylight or other conditions of bright general lighting istoo bright in the dark. It is an object of the invention to provide aparticularly simple means by which the brilliance may be changed.

The invention provides a lamp of the above kind which has thecharacteristic feature that the transparent or translucent member isadjustable by rotation about an aXis substantially perpendicular to theprincipal light rays passing through the member from the bulb and hasdifferent degrees of light transmission of the rays in differentpositions of rotation.

The Construction may be such that in one position of adjustment of themember the light is cut off substantially completely or that in allpositions of adjustment an effective amount of light is transmittedthrough the member.

In one form of the inv ntion the member, which may be a plasticmoulding, is generally spherical, is mounted for rotation as aforesaidabout a diameter and has, perpendicular to that diameter, a diametricallight passageway of higher transmissivity than the remainder of theequatorial zone of the sphere. The passageway may be a hole which may beopen at both ends or closed at one or each end by a thin layer of lighttransmitting material or it may be a plug of material having greaterlight transmission than the body of the member (eg. the body may becoloured or translucent and the plug clear and transparent). In anotherform the light passageway is provided by treatment of the surface of themember (eg. by roughening or colouring) to reduce the light transmissionwhile leaving diametrically opposed clear areas.

In another form of the invention the member is generally cylindrical andmounted for rotation about its axis. There is a diametrical lightpassageway, as aforesaid, perpendicular to the aXis. When there are twoor more lamps side by side, there may be a single cylindrical membercommon to the several lamps, the member having individual passagewaysfor the several lamps and being divided by opaque separators intosections appropriate to the individual lamps. The passageways may be ofcircular cross-section or elongated in the axial direction.

To support the member for rotation it may have (eg. moulded on it) twospigots which work in bearings in the housing or it may have two socketsin which pivot pins or spigots in the housing are received.

The member may have a projection from its curved surface which protrudesfrom the housing and provides a finger piece by which the member may berotated as aforesaid.

In the case of a single lamp having `a spherical member, the housing maybe of tubular form with two diametrically opposed notches cut in one endin which spigots on a spherical lens member are received, the memberbeing held in place by a bezel spun over the member and a lip around thetube. In the case of a row of lamps, they may each be held in a squaresection housing and a single cylindrical lens member may extend alongthe row and be supported at the ends in the end housings. A bezel mayhold the member in place.

The cylindrical form of lens member may be used when there is only onelamp. The nger piece may be a local projection or spigot or it may be arib extendng along the whole length of a cylinder or around asubstantial arc of a sphere. The change from full brilliance to minimumbriiliance may be made to be progressive with rotation of the lensmember. For this purpose the member may be modified in shape or lighttransmissability.

Two specific embodiments of the invention will now be described by wayof example and with reference to the accompanying drawings, in whichFIGURE 1 is a side view of a lamp body,

FIGURE 2 is a section on the line 2-2 in FIGURE l, and

FIGURE 3 is a section of the first embodiment on the line 3 3 in FIGURE1, and

FIGURE 4 is a view corresponding to FIGURE 3 of an alternativeembodiment.

The lamp shown in FIGURES l, 2 and 3 has a cylindrical tubular body 10,moulded in a plastic or similar material, open at one end, and closed atthe other by a translucent cylinder 11, which rests adjacent acomplementary wall 12, moulded near the said other end and having a slot14 for the passage of light.

The cylinder 11 rotates in spigots 16 in bearings 18 and is held inplace by a bezel 19 spun over it and around a lip 20.

A slot 22 within the cylinder leaves a narrow wall 23 through whichlight passes more readily than through the entire thickness of thecylinder. Thus, by rotating the cylinder about its spigots, the size ofthe aperture leading directly to this thin wall 23 is varied andconsequently the proportion of light transmitted thereby is varied.

A projection 30 provides a finger piece for which the cylinder can berotated as desired.

The embodiment shown in FIGURES 1, 2, and 4 is the same as theembodiment of FIGURES l to 3 except that the housing 10 comprises fourtubular holes in parallel side-by-side relation and there is a singletranslucent cylinder 11 extending across the open mouths of the holes.The cylinder has a slot 22 for each hole and there are opaque separators43 to divide the cylinder into four portions correspon ding to the fourholes or lamps. There is a single bezel 19 to retain the cylinder -inthe housing.

I claim:

1. An electric lamp comprising a lamp bulb, an opaque housing containingthe bulb and having an aperture through which light from the bulb may beemitted and a light-transmitting translucent cover member for theaperture, means to mount the cover member in the housing for rotationabout an axis transverse to the rincipal light rays passing through theaperture from the bulb which cover member is circular in cross-sectionin planes perpendicular to the said axis and has a diametrical lightpassageway of lower light absorption than the remainder of the member.

2. A plurality of electric lamps side-by-side each comprising a lampbulb, a housing containing the bulbs and having a plurality of aperturesin parallel side-by-sde relation through which light from the bulbsrespectively, may be emitted, there being for all the lamps a singlecylindrical translucent light transmitting cover member for theapertures, means to mount the cover member in the housing tor rotationabout the axs of the cylinder with the said axis extending along thehousing transverse to the principal light rays passing through theapertures from the bulbs, there being for each lamp a diametrical lightpassageway in the cover member of lower light absorption than theremainder of the cover member, which has opaque separators to divide thecover member into sections appropriate to the individual lamps.

3. An electric lamp comprising a lamp bulb, an opaque tubular housingcontaining the bulb and having an opening at one end through which lightfrom the bulb may be emitted, a light-transmitting translucent covermember for the aperture, said cover member being of cylindrical formWith its axis perpendicular to the axis of the tubular housing, havingaxial spigots projecting from the ends of the cylinder and supported inbearings in the housing, the cover member closing the end opening of thehousing, and said cover member having a diametrical socket which is openat one end and closed at the other, and in one position of rotation isaligned With the throughway of the tube and a bezel around the tubemouth and having an aperture fitting over and smaller than the diameterof the cylinder to hold the cylinder within the housing.

4. A plurality of electric lamps each comprising a lamp bulb, an opaquehousing having a plurality of tubular holes in parailel side-by-sider-elation containing the bulbs respectively and having openings at oneend through which light from the bulbs may be emitted, and there beingfor all the lamps a single lght-transmitting translucent cover memberfor the apertures, said cover member being of cylindrical form with 'itsaxis perpendicular to and intersecting the aXes of the tubular holes,having spigots projecting axially from the ends of hte cylinder and sup-Ported in bearings in the housing, the cover member closing the said endopenings of the holes, and said cover member having for each lamp adiametrical socket which is open at one end and closed at the other and,in one position of rotation is aligncd with the hole and opaqueseparators to divide the cover member into sections appropriate to theindividual lamps and a bezel around the housing and having an aperturetting over and smaller than the diameter of the cylinder to hold thecyl'inder within the housing.

References Cite by the Examiner UNITED STATES PATENTS 2,474,677 6/1949Kirkland 240 46.03 X 2,783,365 2/1957 =Wilfert 240-46.03 X 2,998,5978/1961 Edwards. 3,l19,566 1/1964 Close ?AO-46.03

NORTON ANSHER, Pr'mary Examine r.

C. R. RHODES, Assistant Examiner.

1. AN ELECTRIC LAMP COMPRISING A LAMP BULB, AN OPAQUE HOUSING CONTAININGTHE BULB AND HAVING AN APERTURE THROUGH WHICH LIGHT FROM THE BULB MAY BEEMITTED AND A LIGHT-TRANSMITTING TRANSLUCENT COVER MEMBER FOR THE APER-GTURE, MEANS TO MOUNT THE COVER MEMBER IN THE HOUSING FOR ROTATION ABOUTAN AXIS TRANSVERSE TO THE PRINCIPAL LIGHT RAYS PASSING THROUGH THEAPERTURE FROM THE BULB WHICH COVER MEMBR IS CIRCULAR IN CROSS-SECTION INPLANES PERPENDICULAR TO THE SAID AXIS AND HAS A DIAMETRICAL LIGHTPASSAGEAWAY OF LOWER LIGHT ABSORPTION THAN THE REMAINDER OF THE MEMBER.